Grate and grate-bar therefor.



F. E.CAN'DA.

. GRATE AND GHAIE BAR THEREFOR.

APPLICATION FILED MAY 4, 1916.

Patented June 18', 1918.v

5 SHEETS-SHEET l.

if m QN NAIA In ven tot:

/"MAny F. E. CANDA.

GRATE AND GRATE BAH THEREFOR.

APPLICATION FILED MAY 4. I9I6.

Patented June 18', 1918.

5 SHEETS-SHEET 2.

Iven tor:

F. E. cANnA.

GRATE AND GRATE BAR THEREFOR.

i APPucAT1oN-F|LEn MAY 4. 1916.

1,269,579. Patentedlune'1s,191s.

5 SHEETS-SHEET 3.

Attest: L." fj Inventor:

F. E. CANOA. GBA'TE AND GRATE BAR HEREFoR. APPLICATION FILED MAY 4, i916.

5 SHEETS-SHEETA.

Inventor:

mma-MAY Patented June 18, 1918.

F. E. CANDA.

.'GRATE AND GRATE BAR THEREFOR.

APPLICATION man MAY 4. 1916;.

1,269,579. v PautedJune18, 1918.

.5 sHEETsi-s'HEET s.

ttest: n Inventor Atty UNITED STATES PATENT OFFICE.-

GRATE .A ND GRATE-IBAR THEREFOR. A

Specication of Letters Patent.

Patented June 18, 1918.

Application filed May 4, 1916. Serial No. 95,312.

. To aZZ whom z't may concern.'

Be it known that I, FERDINAND E. CANDA, a citizen of the United States of America, and a resident of New York, county of `New York, and State of New York, have invented a certain new and useful Grate and Grate- Bar Therefor, of which the following is a specification.

My invention relates to improvements in grates and grate bars, particularly grates for rock Crushers and grate bars therefor. My invention comprises a rolled grate bar -blank having spacing-pads formed thereon,

such blanks adapted to be cut at intervals to form grate bars of various lengths desired; my invention further comprises an improved form of grate bar, provided with longitudinal grooves and corresponding projections, whereby adjacent grate bars, or adjacent turns of a spiral grate, may be interlocked for joint support; and my invention further comprises the improved grate comprising the said interlocking grate bars or,

.1n a spiral grate, interlocking successive turns. Other features of my invention will be pointed out hereafter. j

The objects of my invention are, to proi vide an improved grate capable of construction from rolled members, and which shall 4.have better wearing qualities than former grates; to interlock the successive members of a grate in such manner thatsuch successive members shall derive support one from another, as well as from the carrying means for such members; to provide a grate which, while formed of rolled members, shall expose greater grate-area within limits of space available; and generally, to provide a stronger, more durable and more grate.

A I will now proceed to describe my invention with reference to the accompanying drawings, and will then point out the novel features in claims. In the drawings:

j. Figure 1 shows an edge view, and Fig. 2 a

j side view, of a portion of one of my improved grate-bar blanks; dotted lines, in Fig.

2,v indicating lhow grate bars of various lengths may be out from grate bar blanks.

Fig. 3 shows a transverse section, and Fig.

4 ay fragmentary side view, of analternative form of grate bar blank, and Fig. 5 shows ,-a transverse ,section ofa plurality of grate bars formed from suchblank, intel-locked.

Fig, `@shows an edge'view ,on a smaller eliicient grate, the view indicating, in dotted lines,y

the members in which such grate bars are mounted; and Fig. 8 is a view similar to Fig. 7 but showing the use of curved grate bars, such as are rendered practicable by the yconstruction shown in Figs. "3, 4 and 5.

Fig. 9 shows an end view and partial transverse section of one form of rock crusher in which my improved grate may be employed, and Fig. 10 shows a side elevaj tion and partial vertical section of the said Crusher, showing my grate in place therein.

Fig. 11 shows an elevation of a spiral grate adapted to fill the entire grate-aperture of the end of a ball mill such as shown in Fig. 10,; the several turns of this spiral grate being interlocked as shown in Fig. 5; and Fig. 11a shows a fragmentary axial section of the discharge end of a rock crusher with the said grate in place therein.

Fig. 12 shows an elevation of the end wall of a mill having in it a plurality of apertures each containing a similar spiral grate; and Fig. 13 is a view similar to Fig. 12 showing a larger number of smaller spiral grates.

Fig. 14 is a fragmentary transverse section of the end wall of a ball mill showing means for holding in place the helical grates of Figs. 12 and 13. Y

Practical experience with rock crushers, particularly Crushers of the ball mill type, has shown that it is extremely desirable to provide such Crushers withscreens or grates through ywhich `the material, re-

` duced to powder within andby the action of the ball milk-shall be discharged, from the ball mill.V Ithas been -shown that such ball mills so provided with discharge screens or grates,havevery much greater crushing ca- I pacity, for kequal size, than mills" in which the pulverizedy material` is` discharged' through an open'center space. It has been found that, in such mills, gratesformed of rolled hard steel, such for example as chrome steel, have f very much greater durability thangrates, formed of cast bars',v however vhard thematerial of such cast bars-may be; and'alsograte bars formed of rolled hard steelare much less likely to break than are @stilare of the hardness desirable ,in such.

mills. It has been found, however, that grate bars which are not interlocked relatively are subject to excessive wear due to motion of one against the other; no matter how firmly the grate bars are clamped, initially, at their ends, it is found that they work loose, and, when loose, they wear one against another, the wear being, of course, increased greatly by thepresence of gritty material between the bars. Furthermore, greater area of grate surface may be obtained by using curved bars; z'. e., bars bent to the form of arcs of circles; but practical considerations have heretofore prevented, in ball mills at least, the use .of grates formed of curved rolled steel bars. By my present invention, however, I provide means for so interlocking adjacent bars relatively, that it is practicable to make them of curved form and to secure the support required when curved bars are used. My invention also contemplates grates formed of a spirally wound bar, the several turns of the spiral being interlocked.

Referring now first to Figs. l and 2, numeral 1 designates a rolled grate bar blank provided at intervals with projections or pads (as they are termed in the art) 2 formed on the bar l during the rolling of that bar. In Fig. 7 I show a grate Acomposed of grate bars cut from blanks such as shown in Figs. l and 2. It will be seen that the grate bars, designated in Fig. 7 by numeral la, are of different lengths. The spacing of the pads 2 in the blank l is such that -the shortest grate bar l21 has at least two such pads, while other bars have three or more such pads. Dotted lines 3, in Fig. 2, indicate how the blank l may be cut to form bars of different lengths, but having nevertheless the necessary number of pads.

In Fig. 7 I have indicated in dotted lines the customary manner of lmounting grate bars such as indicated by the dotted cutting lines in Fig. 2. I do not claim herein the particular means shown in Fig. 7 for mounting such grate bars, but have thought it desirable to illustrate and describe such mounting means. 4f designates the shell of a ball mill rock Crusher, 5 designates an inner grate-carrying member, and 6 designates spokes with which the outer grate carrying vmember 7 is vprovided and which are secured to the inner member 5. The several grate bars 10 rest upon thesespokes 6 and are clamped thereon by clamping members 8 and bolts 9. It is not necessary that the pads 2 of successive grate bars register, radially or otherwise, and such pads may come, in relation to one another, as may happen; the purpose of the pads being to space the grate bars one fromy another. An outer pressure member 10, acted upon by compressionscrews 11, forces the grate bars together and, in connection with the clamping bars 8, holds such grate bars together as firmly as may be.

In the alternative construction illustrated in Figs. 8-5 inclusive, the blank, here designated by numeral l, is provided, as in the arrangement shown in Figs. l and 2, with pads 2 at suitable intervals,l and these pads are provided with projecting lugs 2; and the reverse side of the blank is provided with a longitudinal groove 2" corresponding in profile to the profile of the lug 2". Obviously adjacent grate bars (designated in Fig. 5 by numeral 1b) may be interlocked by engagement of the lug 2l of the one bar with the groove 2 of the adjacent bar. This is important, for thereby each bar is interlocked with the adjacent bar, at two or more points at least other than the points at which the bars are clamped at their ends. From this interlocking results a much greater' rigidity of the grate strueture; a rigidity such that in practice the grate bars do not work one against the other materially, and thereby the wear of the grate is greatly reduced.

Furthermore, it happens occasionally, in the tempering of steel grate bars, that they crack; the cracks not becoming appare-nt until after the grate bar has been in service for a time; or, it may happen that the grate bar may Crack while in service. lVhen the grate bars are supported at their ends only, the cracking of a grate bar necessitates the stoppage of the mill, and the removal of the broken bar; which is both inconvenient and expensive. But when the interlocked bars, such as shown in Fig. 5, are employed, cracking of one or more of the bars is a relatively unimportant matter; and, in general, the operation of the mill may be con-vk tinued, and the use of such cracked or broken bar continued, quite irrespective of such cracking or breaking, and until the bars are worn out.

For various practical reasons, when the grate bars are not interlocked it is impracticable to bend them into arcs or circles, although a grate formed of such bent bars aords a somewhat greater screen surface than is offered by straight bars. But when the bars are formed for interlocking, as indicated in Fig. .5, it is entirely possible to bend them, producing curved bars such as the bar lc of Fig. 6. Such bent bars may then be assembled to produce a screen such as shown in Fig. 8 which, vas is apparent from a comparison with Fig. f7, offers a materially greater screening surface than does the grate of Fig. 7

The interlocking construction illustrated in Figs. 3 5 inclusive also lends itself readily to the production Aof spiral grates, formed by the winding of a long blank, such as the blankfl of Fig. 3, into a spiral, the several turns of the spiral being interlocked by engagement of the lugs 2" of each turn of the spiral with the groove 2 8 of an adjacent turn of the spiral. Such a grate adapted to ll the entire grate-aperture of the end of a ball mill, is shown in Fig. 11; 12 designates the spiral grate. A portion of the grate is broken away in Fig. 11 to show the interlocking of the several turns of the spiral. This spiral may be held in place against the end wall 13 of the mill by means of a ring 14.

In the construction shown in Fig. 12 a plurality of segmental -plates 15 are provided, each of which has inserted into it a spiral grate 12, similar to the spiral grate of Fig. 11, but smaller. In practice, the plates 15 may be cast about the grates 12, and so locked thereto. These segmental plates 15 are held in place by means of taper-headed bolts 16.

In the alternative construction shown in Fig. 13, there are segmental plates 15a, in each of which there are a plurality of spiral grates 12, arranged to afford as much total grate area as practicable. These segmental plates are held in place by bolts 16.

In the case of a spiral grate such as illustrated in Figs. 11, 12 and 13, each turn of the spiral is to be considered, broadly, and for the purposes of claims, as a separate grate bar.

What I claim is:

l. A grate bar blank such as described, consisting of a rolled steel member, having at intervals on one side, spacing pads provided with projecting lugs, and having on its opposite side a continuous groove adapted to receive lugs similar to the lugs referred to.

2. A grate comprising a plurality of grate bars each provided on one side with spacing pads each having a projecting lug, and on its other side with a continuous groove corresponding in position to such lugs and adapted to receive similar lugs of another bar, such grate bars interlocked by engagement of the lug of one bar with the said groove of an adjacent bar.

3. A grate structure comprising a support for a plurality of Agrate bars, and a plurality of grate bars secured to such support, each such grate bar having on one side a continuous longitudinal groove, and having on its opposite side a projecting pad provided with a further projecting lug adapted to engage the corresponding groove of an adjacent similar bar, the fact that the said grooves are continuous permitting interlocking of the adjacent bars wherever such lugs may be, and without registry of the lugs of one bar with the lugs of adjacent bars.

4. A grate comprising a spirally wound stri-p, such strip provided on one side with spacing pads each having a projecting lug and on its other side with a continuous groove corresponding in position to such lugs and adapted to receive such lugs, the several turns of the spiral interlocked by engagement of the lugs of one turn with the grooves of an adjacent turn of the spiral.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

FERDINAND E. CANDA.-

Witnesses:

H. M. MARBLE, PAUL H. FRL/ANKE.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

